Plexxikon Leadership Duo, Peter Hirth and Kathy Glaub, Exit Daiichi

Peter Hirth and Kathy Glaub, the executive duo who led Berkeley, CA-based Plexxikon on its quest to develop an important new treatment for melanoma, worked together for more than a decade, and they are heading out the door together.

Japan-based Daiichi Sankyo, the company that acquired Plexxikon for $805 million upfront a little more than two years ago, said today that Hirth, the CEO, and Glaub, the president, are leaving the company. Daiichi also made a series of promotions to fill the void, noting that Gideon Bollag is moving up to be the new CEO of the Plexxikon unit. Daiichi noted that under Bollag, it anticipates that the Plexxikon unit will continue to operate with “a high degree of independence” within the parent company.

“Peter and Kathy were instrumental in building a culture of scientific rigor, operational excellence and management transparency at Plexxikon that I intend to continue under my leadership,” Bollag said in a statement.

Hirth and Glaub were best known for working together at Plexxikon to create vemurafenib (Zelboraf), a drug that won FDA approval for treating melanoma in August 2011. The drug was designed specifically for about half of melanoma patients with a mutated form of a gene called BRAF V600E. Many drug developers have failed to come up with anything effective for this deadly form of skin cancer, but the Plexxikon drug, marketed in partnership with Roche/Genentech, represented a big step ahead, as it offered patients with the mutation an increased chance of seeing tumor shrinkage, and a good chance of living longer. It also represented an important case study in what you could call “precision medicine” as it was paired with a diagnostic test that enabled physicians to select which patients would be most likely to respond to the drug.

Impressive as the drug is, patients do, however, end up developing resistance, which was something Daiichi/Plexxikon has been seeking to understand and combat the past few years.

Hirth and Glaub—who brought complementary skills to the table in science and business—were such a good pair that they often conducted interviews and investor presentations together, and could even finish each other’s sentences. I asked them what they plan to do next via e-mail, and will update this space if I hear anything back.